Differences between anophthalmic and aphenopsian beetles: evidences from larvae of Chinese species

Larval morphology plays an important role in taxonomy and phylogeny construction. Larvae of three hypogean Trechini species, representing aphenopsian, semi-aphenopsian and anophthalmic, respectively, are described and illustrated from China. In general, primary setae were identified according to classical theory established by Bousquet and Goulet. Main larval morphological characteristics of them provide evidences between aphenopsian and anophthalmic species. The Dongodytes troglodytes Tian, Yin & Huang, 2014 (a typical aphenopsian) larva is distinct from Guizhaphaenops lipsorum Deuve, 1999 and Libotrechus nishikawai Uéno, 1998 by following characteristics: (1) anterior margin of nasale is less protruding, relatively smooth and teeth-lacking (versus distinctly toothed in G. lipsorum and L. nishikawai); (2) hypertrophied abdomen (versus slender in G. lipsorum and L. nishikawai); (3) short and stout pygidium (versus relatively slender in G. lipsorum and L. nishikawai). These major differences above may suggest various larval adaptation degrees of the cave-strictly trechine beetles to the subterranean habitats.